hey cfstras, another dgit dev here. Each repo has a storage adapter specified, so any storage infrastructure is possible, but at this moment we've only written two: sia and on tupelo network.
We've had a lot of experience with running IPFS nodes internally, that might be a great option for you in this case? We are in early stages and will add more adapters as feedback informs.
Also, its open source and we would love PRs :) - the storage interface is pretty straight forward:
https://github.com/go-git/go-git/blob/master/storage/storer....
Here is an example within dgit: https://github.com/quorumcontrol/dgit/blob/master/storage/ch...